Expanding batons are not banned by name by any state law I've ever heard of.
However, that doesn't mean they aren't technically bludgeons. I don't know of any case law on it, but the odds of a court ruling an ASP type weapon to be not a bludgeon aren't great. Plus, even if they were unquestionably legal by state law, there is no baton preemption.
If your situation, I would get some super duper powerful pepper spray, and use it on myself until I was confident with it that it wouldn't take me out of action if I got cross exposed. That would be my primary weapon, and the back up would be a mag light.